PC Engine Duo white screen

It displays a video signal but only gives a white screen. I know people will suggest cleaning the Hucard connectors etc. but this also happens with the CD drive. I have replaced all the caps but to no avail. Basically some kind of video signal is present, but everything else is unresponsive.
I have read that the problem could be with the C6270 chip.?

 

What about with no CD or HC?
If it does the same thing, re check all your soldering, your either missed something or have a cap backward.

 

The white screen was present before I recapped it.

 

Have you resolved your white screen issue?
If not look for broken traces and solder bridging or corrosion around the HuC62XX chips.

 

Gosh! My topic back from the dead.
I didn't manage to fix the issue. I checked vias, traces etc for continuity but found none broken. There is no corrosion or other obvious damage. I think the issue might be with an IC and I don't have a logic probe to test them.